Propeller blade



NOV. 18, 1947. A BERLINER' 2,430,854

' PROPELLER BLADE 3 Sheets-Sheet 1 Filed June 13 1945 grwvwloo HENRY A.EERLIVNER 3 Nov. 18, 1947-.

PROPELLER BLADE Filed June 15, 1945 H. A. BERLINER 3 Sheets-Sheet 2HENRY Z1. BERL/NER 9 fir/040a Nov. 18, 1947;

Filed June 15, 1945 i i- 7*- .u

H. A, B ERLINER PROPELLER BLADE 3 Sheets- Sheet 3 Patented Nov. 18, 1947UNITED STATES PATENT OFFICE PROPELLER BLADE H n y A- E li h ton assi n rto Engineering and Research Corporation, Riverdale, Md, a corporation ofMaryland Application June 13, 1945, Serial No. 599,176

4 Claims. 1

This invention relates to propeller blades and, more particularly, tohollow metal propeller lades- I-Iollow metal propeller blades arewell-known and widely used and have numerous advantages over other typesof blades. Such blades may be formed in many ways, one of these being bythe formation of separate root and blade parts which are joined to formthe finished blade. Among other serious difiiculties encountered in themanuiacture of blades of this specific type has been the provision of astrong and efficient but simple connection between the root and bladeand. the construction of a blade having a root portion of minimum sizeand weight but also having sufficient blade rigidity and strength toWithstand heavy loads.

It has been the principal object of this invention, which is achieved bythe blade disclosed herein, to provide a strong and light blade havingthe required rigidity and strength, which may be simply ma ufactured andeasily assembled.

Other objects and features of novelty of the invention will be madeapparent by the following description and the annexed drawings which, itwill be understood, are only illustrative of the invention and impose nolimitation thereon not imposed by the appended claims.

Referring to the drawings, in which similar reference numerals refer tolike parts,

Fig. 1 is a side elevational View of a blade according to thisinvention, having parts thereof broken away;

Fig. 2 is a perspective view of the adapter part of the blade of Fig. 1;

Fig. 3 is a sectional view taken on lin 3-45 of Fig. 4;

Fig. 4 is an outer end view of the adapter part of the blade of Fig. 1;

Figs. 5 and 6 are views showing two modified adapters according to myinvention;

Fig. 7 is a side elevational view of a modified form of blade accordingto the invention;

Fig. 8 is an outer end view of an adapter part for use with the blade ofFig. 7;

Fig. 9 is a sectional view taken on line tll of Fig.

Fig. 10 is an enlarged view of parts of the adapter shown in Figs. 8 and9, showing particularly the connection between the blade wall and theadapter;

Fig. 11 is a view similar to Fig. 9 showing a modified form of theadapter of Fig. 9;

Fig. 12 is an enlarged view showing one means for attaching the bladewall to the adapter, and

Figs. 13, lo. and 15 are partial views of the blade part 01 a propellershowing the means provided by the invention for strengthening andstiffening the edges thereof.

A propeller blade formed according to my invention is disclosed in Fig.l of the drawings and comprises. a blade part 2 and a root, or adapter,

part ti. The blade is of airfoil shape at each crosssoction thereof andis hollow, being formed of sheet metal which, in a preferred method ofmanufacture illustrated in Figs. 13 and 14, is bent or stretched about aform having the shape of the leading edge part of the blade, the freeedges being then shaped and connected to form the trailing. edge part.The root or adapter part of the blade comprises a metallic member havinga part B which is of airfoil shape in cross-section and of substantialarea, a part llof circular cross-section and reduced size which isscrew-threaded or otherwise formed for attachment within the propellerhub, and an intermediate part Ill of tapering form. The adapter 4 ispreferably hollow and the parts 6, ll] thereof are provided withinternal reinforcing webs i2, M.

The open, inner end of the part 2 of th blade closely surrounds theairfoil-shapedpart 6 of the adapter and is rigidly attached thereto bybrazing, welding, riveting or otherwise, thus forming a lightweight andstrong blade.

In a modified form of the invention, which is disclosed in Fig. 5, theblade part 2 is attached to the adapter over only a part of the surfaceof the peripheral wall of the airfoil-shaped part thereof, and the partof the wall which contacts the blade part is set inwardly of the rest ofsuchperipheral wall, as at In in Fig. 5, forming a step I2 on which theend wall of the blade part 2 seats. The parts are preferably sodimensioned that the outer surface of the blade part 2 is flush withthat of the part of the peripheral Wall which is not inset.

A further modification of the adapter part of the blade provided by theinvention is disclosed in Fig. 6. In this embodiment the side walls 01'the part of the adapter to which the blade part 2 is attached areextended toward the blade part 2 beyond the leading and trailing edgeparts of the adapter to provide additional areas of contact between theblade and adapter parts, whereby brazis positioned and connected withinthe adapter. Such a blade is disclosed in Fig. '7 and comprises anadapter part 30 which receives, surrounds and is attached to the openinner end of the blade part 2.

One form which the root or adapter 36 may take is disclosed in Figs. 8,9 and 10. This adapter is generally similar in shape to that of Figs. 2,3 and 4. The outer, airfoil-shaped part 32 of the adapter comprises theperipheral wall 34 and a second wall 33 which is spaced inwardly ofperipheral wall 3 3, is of less height than the outer peripheral walland extends parallel thereto throughout its length. The width of thespace between the two walls is of the order of the thickness of themetal sheet of the blade part 2 in order that the same may be receivedtherebetween, and such space is sufliciently deep to receive asubstantial part of the edge of the blade part 2. The lower part of theouter surface of the inner wall 38 is flared toward the outer Wall, asshown at 33 in Fig, 10, in order to permit the blade part 2 to be wedgedbetween the walls and therefore be more securely held. The inner Wall ispreferably non-continuous, being interrupted by a plurality of openings96 which extend below the bottom of the space between the two walls.Lateral internal ribs 42 and a longitudinal internal rib 44 are providedto strengthen the adapter part.

In a modified form of the adapter of Figs. 8, 9 and 10, which isdisclosed in Fig. 11, a plurality of the spaced parts forming the innerWall 36 are extended outwardly, as shown at beyond the outer or uppersurface of the outer wall 34 and provide additional surfaces abuttingthe inner surface of the blade part 2 and to which the blade part may bebrazed or otherwise attached. These extending parts also increase thestiffness of the blade part of the propeller.

In a further embodiment of the invention the blade part is attached tothe adapter part by riveting. A structure embodying this means offastening is disclosed in Fig. 12, in which are shown the wall 66 havinga step 62 formed in the outer surface thereof within which the inner endof the blade part 2 is received, the blade part 2 and wall 60 beingconnected by rivets 64. These rivets may extend through the entireblade, thereby attaching the blade part to each side of the adapter or,alternatively, each rivet may be of the blind type. The outer wall ofadapter part 66 is countersunk about the rivet holes therein, as shownat 66, and the metal of the blade part 2 is drawn into thesecountersinks in order to more firmly attach the blade parts together.

Means are provided by the invention for stiffening and strengthening theleading edge or the trailing edge, or both, of the blade part of thepropeller. Such means comprise stifiening means 19 attached to theleading edge part of the blade part 2 and similar means 12 attached tothe trailing edge part internally thereof, and either or both extendingthroughout all or a part of the length of the blade part. As shown inFigs. 13 and 14, this stiffening and strengthening means may comprise ametal strip welded, brazed or otherwise attached to the blade part priorto completion thereof. Alternatively, and as shown in Fig. 15, eachstiffening and strengthening means may be provided by a metal filletwhich may be deposited in molten state.

While I have described and illustrated several embodiments of myinvention, it will be apparent to those skilled in the art that furtherembodiments, as well as modifications of those disclosed, may be madewithout departing in any way from the spirit or scope of the invention.

What is claimed is:

1. A propeller blade comprising a hollow blade part and a separateadapter part, said adapter part comprising an integral structure havinga substantially cylindrical portion for attachment within a hub and asubstantially hollow portion of airfoil section having tworadially-spaced walls extending axially of the blade and between whichthe open end of the hollow blade part is received and fastened.

2. A propeller blade according to claim 1, in which the adjacent facesof the two walls converge at their inner ends to provide a restrictedrecess for the reception of the end Wall of the hollow blade part.

3. A propeller blade according to claim 1, in which the inner wall isformed of a plurality of spaced sections.

4. A propeller blade according to claim 3, in which some of the spacedsections of the inner wall extend axially of the blade beyond others.

HENRY A. BERLINER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,414,742 Leitner May 2, 19221,438,838 Leitner Dec. 12, 1922 1,875,454 Havill Sept. 6, 1932 2,231,888Couch Feb. 18, 1941 2,336,012 Hackethal Dec. '7, 1943 2,380,683 CarolJuly 31, 1945 FOREIGN PATENTS Number Country Date 221,906 Great Britainl Sept. 25, 1924 281,357 Italy Jan. 10, 1931 360,952 Germany Oct. 9,1922 491,155 Great Britain Aug. 26, 1938

